1. Field of the Invention
The present invention relates generally to sanding devices. More particularly, the present invention relates to improvements in sanding blocks.
2. Description of the Related Art
Woodworking projects typically involve sanding of the wood before a finish is applied to the wood. Other surfaces, such as drywall and automotive bodies, are also commonly sanded before a finish is applied. Such sanding has been aided by use of power sanding devices, but almost invariably, some amount of hand sanding is generally needed in any quality sanding job.
Hand sanding has been performed using a variety of sanding blocks, sanding sticks, sanding pads, and individual pieces of sandpaper. The sanding process often must be carried out using multiple grades of abrasive to achieve a quality smooth surface that is free of sanding marks.
Early sanding blocks were simply blocks of solid material, such as wood, over which rectangular sheets of sandpaper were wrapped. While these devices were adequate for some purposes, they required some means of holding the ends of the sandpaper while applying one face of the block against the surface being sanded. This resulted in inefficient use of the sandpaper because the ends were generally never exposed to the surface being sanded. Various sanding blocks of this type employing means for grasping the ends of the abrasive sheet are disclosed, for example, in U.S. Pat. Nos. 2,765,593 and 1,562,414.
There has been developed and marketed a self-adhering sandpaper that uses a hook and loop adhesive system to adhere the sandpaper to a power sanding tool, such as a rotatable disc sander. The adhesive system normally includes a loop-type material covering a backside of the sandpaper, and a hook-type material covering a working surface of the sanding tool. Adhesive systems have also been developed in which a hook-type material covers the backside of the sandpaper, and a loop-type material covers the working surface of the sanding tool. Examples of such self-adhering sandpaper include sanding discs marketed by the 3M Company under the proprietary names, Hook-It and Hook-It II. However, when these self-adhering sandpapers are adhered directly to the working face of a sanding block, it is sometimes difficult to apply adequate pressure to the surface being sanded due to the cushion effect provided by the adhesive system, and it is also sometimes difficult to keep the edges of the sandpaper from becoming torn or crumpled during use.
Various other self-adhering sandpapers have also been developed that use pressure-sensitive coatings to adhere directly to the working face of a sanding block. This means of attaching sandpapers assures exposure of the entire abrasive face of the sandpaper. Such sandpapers are disclosed, for example, in U.S. Pat. Nos. 2,485,295, 3,849,949 and 3,912,142. This type of sandpaper has been used in conjunction with both rotatable disc sanders and hand held sanding blocks. However, once a piece of sandpaper with a pressure-sensitive coating is applied onto a block or sander, it cannot be readily changed until the sandpaper is ready to be disposed of because the sandpaper does not peel without tearing and will not re-stick. This makes changing back and forth between different grits of sandpaper difficult and costly.
Sanding blocks for hand sanding have not been developed to utilize self-adhering sandpaper to its fullest advantages. Thus, there is a need in the industry for an improved sanding block.